Final answer:
The purchase or attempt to purchase alcohol underage is illegal and prohibited by law in the United States, with a legal drinking age of 21 as mandated by the National Minimum Drinking Age Act of 1984.
Step-by-step explanation:
The purchase or attempt to purchase alcohol underage is illegal and prohibited by law. In the United States, the legal drinking age is 21 years old, as mandated by the National Minimum Drinking Age Act of 1984. This law requires states to raise their drinking age to 21 or risk losing federal highway funds.